Enclosed electric switch



June 9, 1942. a. E. GETCHELL ENCLOSED ELECTRIC SWITCH 3 Sheets-Sheet l Filed Dec. 18, 1939 BENJAMIN GETCHELL,

June 1942- B. E. GETCHELL 22 ENCLOSED ELECTRIC SWITCH Filed Dec. 18, 1959 3 Sheets-Sheet 2 BENJA M/N GE TCHEL L,

Patented June 9, 1942 I i U N IT E D STATE PAT E NT QEFF ICE ENCLOSED ELECTRIC SWITCH Benjamin E. Getchell, Plainville, Conn-.,.-assignor to The Trumbull Electric Manufacturing Company, Plainville, Conn., a corporation of Connecticut 2 Claims.

My invention relates to switches especially intended for connecting line to load circuits. Such switches are-usually enclosed and consequently should be constructed for convenience in wiring in various ways. The invention isparticularly applicable to double throw switches and reversing switches-in fact a special object is to provide a switch which can be readily wired either as a reversing switch or as a double throw switch.

The form shown is'for a three-wire system and has two sets of switch units, each unit having a pair of stationar contacts and a connecting movable switch member. These are all mounted at the front of an insulating base and each switch contact has a circuit terminal at the rear of the base where all of the wiring is preferably located. A supplementaryset of terminals is also preferably located at one side of the base.

Each set of switch units has an operating crank shaft at the rear of the base and an actuating cam-like member is located at "one side of the base and adapted to selectively operate the crank shafts by movement in one direction'or another.

The various terminals are so arranged that both the top and bottom ones can be used 'for different lines or loads. and the terminals at the side (when present) can be used for connecting a line or a load with the top or bottom terminals, as desired.

The insulating base is preferably supported by a bracket which also supports both crank shafts and the operating member. This same bracket serves as stops for the crank shafts and for the operating cam member. vA single spring is arranged to bias both crank shafts. A part of the cam actuator serves as a handle or actuating lever.

Th drawings show one form of construction and three circuit diagrams.

Fig. 1 is a front view of a switch embodying one form of my invention in a box, the cover being omitted and the parts'of the switch shown in the open circuit position,

Fig. 2 is a vertical section and side view with the cover in place.

Fig. 3 is a horizontal sectional view of the box taken looking upwardly at the partsof Fig. 1.

Fig. 4 is a rear view of the insulating base for supporting the switch contacts and terminals.

Fig. 5 is a side view showing the preferred form of switch operating member in the off position.

Fig. 6 is a similar view but showing the operating member turned to actuate one set of switch units.

Figs. 7 and 8am similar views of a modified form of switch operator.

Fig. 9 is a diagrammatic view of the switch members and terminals'wired in the preferred manner for use as a reversing switch.

Fig. 10 is a diagrammatic view of the switch members and terminals wired as a double throw switch.

Fig. 11 is a diagrammatic view of the switch members and terminals with modified wiring as a reversing switch.

The box or receptacle shown is of conventional form with a body 14 and a cover I5 hinged at one edge. The insulating base I6 is mounted on posts I! and secured to a 'backplate I8 by screws I9. Ihis back plate has slots 20 and 2| to receive clamp screws 22, 23 in the bottom of the box so as to facilitate the mounting and demounting of the switch in and from the box.

Each switch unit consists of stationary contacts 25 and 26 and a movable switch member 21 carried b a plunger 28. A crank shaft 29 operates the upper set of switch plungers and a crank shaft 30 operates the lower set of plungers and attached switch members. These crank shafts are pivotally carried b the opposite uprights of a U-shaped bracket 3| which is secured to the back plate l8 for'instance by screws 32.

The actuating lever member 33 is pivoted at 34 to one of the uprights of the bracket 3| and has a finger piece 35 which projects through an opening 36 in the cover of the box. A guard plate 3! may be provided loosely carried by the lever to close the opening in the cover around thefinger piece.

Rollers 38 and 39 are carried by the crank shafts 29 and 30 which are drawn toward each other by a single spring 40. The lever 33 has an arcuate edge 4| against which the rollers are drawn by the action of the spring 40 when the parts are inthe open circuit or off position.

The lever also has cam-like projections 42 and 43 which engage the rollers. The parts are so shaped and located that the springlll'tends to hold the crank shafts and the lever in the normal off position. When the lever is tilted to operate one or the other crank shaft and connected switch members, the cam-like projection causes the roller on the side toward which the lever is tilted to rot-ate and presses it toward the outer end of the projection (such as 42 in Fig. 6). When the tip 44 passes the roller 39, the lever is in effect locked in position by the action of the spring 40 acting to draw the crank shaft and the roller 39 around the tip 44 of the projection. A pin 45 may be provided in the side of the bracket 3| to limit the movement of the lever 33. It is desirable to arrange the projection 42 so that there is a considerable resistance to starting the turning of the lever 33 so as to avoid accidental operation and so that the force required to start the movement will result in a forceful action as soon as the tip 44 of the cam slips over the roller-thus ensuring a positive action of the switch.

The form shown in Figs. '1 and 8 has a less abrupt contact portion 42 and a sharper tip 44. This requires less force to start the circuit closing action and more force to start the circuit opening action.

In order to facilitate the wiring of the switch in various ways, I provide each of the switch contacts with a terminal'at the rearof the base as shown in Figs. 9, 10 and 11. The upper set of contacts have terminals 5|], 5|, 56, 5|, 5|!

' and 5|". 1 The lower -set have contacts 52, 53,

52, 53, 52" and 53". I In the diagrams of Fig. 9, the contacts 26 and 25a are connected by a conductor 54. Contacts 26' and 251) are connected by conductor 54 and contacts 26" and 250 are connected by conductor Auxiliary terminals 55, 56 and 51 are carried by an insulating'block 58 at one side of the switch and'the switch is wired as shown in Fig. 9 in order to use it as a reversing switch. When the upper set of switch members 21, 21' and 21" is closed, the three circuits may be traced as follows: 25, 21, 26, 54, 52 to 55; 25', 21, 26, 54', 52' to 56; and 25", 21", 26", 54", 52" to 51. To reverse the circuits the switch members 21, 21 and 21 are raised and the contacts 21a, 21b'and 210 are closed whereupon the circuits may be tracedas follows: 56, 53, 26a, 21a, 25a, 52 to 55; 50, 53", 26c, 21c, 25c, 52" to 51; and 59', 53, 26b, 21b, 25b, 52 to 56.

The same switch can also be wired for reversal 'as shown in Fig.'11 without the auxiliary terminals but in this case the conductors 54, 54 and 54" of Fig. 9 are omitted "and insulating barriers such as 60 are inserted between the adjacent switch contacts. In this case the circuits can be traced as follows when the upper set of switch members 21, 21' and 21" is closed, viz: 25, 21, 26, 5|, 53 to 26a; 25, 21', 26', 5|, 53" to 260; and 25", 21", 26", 5|", 53 to 26b. It will be understood that the contacts 25, 25' and 25" are also provided with suitable wire terminals as are contacts 26a, 26b and 260. When the lower switch members are closed, the circuits may be traced as follows: 25, 50, 52, 25a, 21a to 26a; 25', 50, 52', 25b, 21b to 261); and 25", 56", 52", 25c, 210 to 260.

When it is desired to use the switch for double throw action, it is wired as shown in Fig. 10. In this case, the connectors 54, 54 and 54" are used as well as the auxiliary terminals 55, 56 and 51. When the upper switch members are closed the circuit may be traced as follows: 25,

21, 26, 54, 52 to 55; 25, 21', 26, 54', 52' to 56; and 25", 21", 26", 54", 52" to 51. When the lower set of switch members are closed the circuits may be traced as follows: 55, 52, 25a, 21a to 26a; 56, 52, 25b, 21b to 26b; and 51, 52", 25c, 210 to 260. It is obvious that the side terminals 55, 56 and 51 may be omitted, and terminal posts, mounted directly on the front of connectors 54, 54' and 54 be used instead.

Preferably the switch units are all mounted in grooves 6| in the front or outer surface of the base. -The switch contacts 25, 26a, etc., at the upper and lower ends of the base are preferably provided with conventional circuit terminals at the front of the base. The connectors 54 etc., when used are also located in the same grooves. Each of the switch contacts has a circuit terminal at the rear of the base. This arrangement makes it possible to utilize the same base and switch mechanism in a number of different ways as set forth.

I claim: U

1. A switch having an insulating base, a bracket mounted in fixed relation thereto, two separate switch units on said base, each unit having airs of spaced stationary contacts and a movable switch member coacting with the contacts of each pair, two separate crank shafts supported by said bracket beneath the base for actuating the respective movable switch members, a pivotal cam member on said bracket at one side of the base for moving either one of said crank shafts independently of the other, an integral hand lever on the cam member and spring means connecting said crank shafts for urging said shafts to open circuit position, said cam member and said spring means tending to act against one another with respect to the bias of both crank shafts, whereby both movable switch members are positively maintained in their respective circuit controlling positions and whereby the switch members are protected against accidental opening or closing.

2. In an electric switch having an insulating base, switch units including an upper pair of spaced stationary contacts and a switch member adapted to be moved into engagement with said contacts, a crank shaft beneath the base for actuating said movable member, a lower pair of spaced stationary contacts and a switch member adapted to be moved into engagement with said lower contacts, a second crank shaft beneath the base for actuating said latter movable switch member, a cam member at one side of the base for selectively actuating said crank shafts, integral shoulders intermediate the ends of the cam face for holding the cam in inoperative position and a shoulder at each of the opposite ends of the cam face for holding said cam in extreme operative position, whereby said crank shafts are at all times subjected to opposite biases caused respectively by the action of said cam member and said spring means.

BENJAMIN E. GETCHELL. 

